Platen clamping mechanism for an injection-molding machine

Abstract

To displace a moving mold mounting plate ( 3 ), a threaded spindle drive is inserted between the moving mold mounting plate ( 3 ) and a fixed mold mounting plate ( 16 ), whereby one end of each threaded spindle is mounted in the fixed mold mounting plate ( 16 ) and is configured as a piston ( 9 ) of a hydraulic piston and cylinder unit. The pistons are mounted in the fixed mold mounting plate ( 16 ) in hydraulic cylinders and an increased clamping force is created for the platen clamping mechanism by an appropriate impingement of the piston ( 9 ). In addition, the invention provides a detachable anti-rotation mechanism ( 23 ) for the threaded spindles ( 15 ). The invention thus allows an inclined position of the mold mounting plates ( 3, 16 ) to be corrected, by the targeted rotation of one or more threaded spindles.

1. A platen clamping unit for an injection molding machine, comprising:
 a moving mold mounting plate:  
 a fixed mold mounting plate;  
 a spindle drive for displacing the moving mold mounting plate relative to the fixed mold mounting plate, said spindle drive including at least one threaded spindle having one end configured as a piston rod, and an electric motor;  
 a clamping force unit for generating a clamping force, said clamping force unit including at least one hydraulic piston and cylinder unit which is fitted in one of the mold mounting plates and has a cylinder and a piston, which is guided in the cylinder, wherein the piston rod of the threaded spindle supports the piston of the hydraulic piston and cylinder unit; and  
 an anti-rotation mechanism acting on one end of the piston and having an actuating head to allow a turning of the threaded spindle, when the anti-rotation mechanism is released.  
 
   
   
     2. The platen clamping unit of  claim 1 , wherein the threaded spindle is movably supported by the releasable anti-rotation mechanism in the fixed mold mounting plate and has a threaded portion which extends through the moving mold mounting plate and through a threaded nut rotatably mounted at the moving mold mounting plate and driven by the electric motor. 
   
   
     3. The platen clamping unit of  claim 2 , and further comprising a releasable toothed holding brake mounted between the threaded nut and the moving mold mounting plate. 
   
   
     4. The platen clamping unit of  claim 1 , wherein the anti-rotation mechanism has a toothed pin element, which is part of the piston, and a cap element, which is detachably secured to the fixed mold mounting plate and has a recess which complements the toothed pin element, wherein the toothed pin element is shiftable in the recess at least by a distance of a piston stroke of the clamping force unit. 
   
   
     5. The platen clamping unit of  claim 4 , wherein the spindle drive includes a plurality of said threaded spindle. 
   
   
     6. An injection molding machine, comprising a platen clamping unit having a moving mold mounting plate, a fixed mold mounting plate, a spindle drive for displacing the moving mold mounting plate relative to the fixed mold mounting plate, said spindle drive including at least one threaded spindle having one end configured as a piston rod, and an electric motor, a clamping force unit for generating a clamping force, said clamping force unit including at least one hydraulic piston and cylinder unit which is fitted in one of the mold mounting plates and has a cylinder and a piston, which is guided in the cylinder, wherein the piston rod of the threaded spindle supports the piston of the hydraulic piston and cylinder unit, and an anti-rotation mechanism acting on one end of the piston and having an actuating head to allow a turning of the threaded spindle, when the anti-rotation mechanism is released.